The acute retinal necrosis syndrome. Possible herpes simplex retinitis

Herpes zoster keratitis development after acute retinal necrosis

PURPOSE

To report a case of herpes zoster keratitis in a patient undergoing treatment for herpetic acute retinal necrosis.

METHODS

Case report.

RESULTS

A 71 year old male presented with acute retinal necrosis of the left eye due to herpes zoster and was treated with intravitreal foscarnet and oral valcyclovir. He developed a retinal detachment and underwent surgical repair. After four weeks, he developed an ipsilateral herpetic zoster keratitis demonstrated by Rose-Bengal staining that was responsive to topical ganciclovir gel.

CONCLUSIONS

This case report describes the unusual development of herpes zoster keratitis after the development of unilateral acute retinal necrosis (ARN) in a patient on antiviral treatment.

Clinical manifestation of self-limiting acute retinal necrosis

Background

The purpose of this paper was to present a case series of self-limiting, peripheral acute retinal necrosis and to demonstrate efficacy of treatment with valacyclovir in patients resistant to acyclovir. The diagnosis was made on ophthalmoscopic examination and positive serum tests for herpes viruses.

Material/Methods

Ten patients (6F and 4M) aged 19–55 years were diagnosed and treated for self-limiting acute retinal necrosis (ARN). The following endpoints were reported: visual outcomes, clinical features, disease progression, treatment, and complications. Patients received only symptomatic treatment because they did not consent to vitreous puncture.

Results

Peripheral, mild retinitis was diagnosed in all eyes at baseline. Initially, all patients were treated with systemic acyclovir (800 mg, 5 times a day), prednisone (typically 40–60 mg/day), and aspirin in an outpatient setting. In 6 patients, treatment was discontinued at 6 months due to complete resolution of the inflammatory process. Four patients with immune deficiency showed signs and symptoms of chronic inflammation. Two patients did not respond to acyclovir (2 non-responders); however, those patients were successfully treated with valacyclovir. Complete resolution of inflammatory lesions was observed in 8 patients. In 2 patients, the disease progressed despite treatment – 1 female patient after kidney transplant who stopped the prescribed medications, and 1 male patient with SLE and antiphospholipid syndrome who experienced breakthrough symptoms on-treatment. He died due to cerebral venous sinus thrombosis. Neurological complications (encephalitis and meningitis) were observed in 2 female patients. Prophylactic laser photocoagulation was performed in 1 subject.

Conclusions

A series of cases of self-limiting acute retinal necrosis (ARN) is presented. This clinical form of ARN can resemble toxoplasmic retinitis in some cases. Oral antiviral medications provide an effective alternative to intravenous formulations in patients with self-limiting ARN. Retinitis is associated with the risk of encephalitis.

Acute retinal necrosis in primary herpes simplex virus type I infection

Here we report the case of an immunocompetent 8-year-old child who developed acute retinal necrosis concomitant with a primary herpes simplex virus type I infection. Ocular inflammation changed along with the development of a specific antibody titer in the serum. This evidence suggests that the immune response of the host can significantly modulate the clinical aspect of the ocular infection.

Effect of anti-CXCL10 monoclonal antibody on herpes simplex virus type 1 keratitis and retinal infection

The inflammatory response to acute ocular herpes simplex virus type 1 (HSV-1) infection in mice involves the innate and adaptive immune response, with an associated increase in the secretion of chemokines, including CXCL10 (interferon-inducible protein 10 kDa [IP-10]). Neutralizing antibodies to mouse CXCL10 were used to determine the role of CXCL10 during the acute phase of HSV-1 ocular infection. Treatment of HSV-1-infected mice with antibody to CXCL10 significantly reduced CXCL10 levels in the eye and trigeminal ganglion and reduced mononuclear cell infiltration into the corneal stroma. These results coincided with reduced ICAM-1 and CXCR3 transcript expression, macrophage inflammatory protein-1alpha and CXCL10 levels, and corneal pathology but increased viral titers in the stroma and trigeminal ganglion. Progression of the virus from the corneal stroma to the retina during acute infection was significantly hindered in anti-CXCL10-treated mice. In addition, colocalization of viral antigen with infiltrating leukocytes in the iris and retina during acute infection suggests that one means by which HSV-1 traffics to the retina involves inflammatory cells (primarily CD11b(+) cells). Collectively, the results suggest that CXCL10 expression in the eye initially orchestrates the inflammatory response to acute HSV-1 infection, which facilitates the spread of the virus to other restricted sites within the eye.

Visual dysfunction in retinal and optic nerve disease

Visual perceptions seen with retinal and optic nerve disease may overlap with those resulting from retrochiasmal disorders. A few disorders typically present with distinctive perceptions, but the majority have less specific symptoms. Features include whether or not the visual phenomena are negative or positive, monocular or binocular, and the location and form of any deficits. Among negative phenomena, transient visual loss usually is the result of ischemic disease, but particular precipitants may suggest demyelination or photoreceptor degeneration. The pattern and location of visual field defects may help localize disorders to the level of the macula, papillomacular or other inner retina nerve fiber bundles, optic nerve, or chiasm. Altered brightness perception may point to optic nerve or photoreceptor disease. Decreased acuity is among the most common and least specific symptoms, but association with other symptoms may help to narrow the differential diagnosis. Dyschromatopsia points to either a photoreceptor or optic nerve pathologic condition (Table 7). Among positive phenomena, hallucinations resulting from anterior visual system disorders typically are unformed, although deafferentation of retrochiasmal pathways may produce formed hallucinations. The common "floaters" frequently are benign, but occasionally herald more concerning disorders. Various types of photopsias commonly occur with vitreal disorders or photoreceptor disorders. Macular disease typically leads to distortions of the central visual field, and other particular disorders lead to a host of characteristic distortions of color, form, or brightness. Careful attention to the ophthalmologic examination, visual fields, and subtle variance in symptomatology also help to distinguish among various disorders.

Herpes simplex virus type 2 acute retinal necrosis in an immunocompetent patient

PURPOSE

To report a case of acute retinal necrosis caused by herpes simplex virus 2 in an otherwise healthy patient.

CASE REPORT

A 45-year-old man presented with one month's history of decreased vision in the right eye. He had previously received a course of intravenous gancyclovir because of a clinical suspicion of cytomegalovirus retinitis. The patient's ocular history was remarkable for a similar episode in the left eye thirty years earlier, resulting in important visual impairment. System and laboratory investigations were unremarkable. Ocular examination showed severe anterior granulomatous uveitis, vitreous haze, areas of necrosis and retinal exudates. The anterior chamber tap disclosed the presence of HSV type 2, and oral steroids and acyclovir were instituted. Two weeks after the patient had been discharged, a retinal detachment occurred in the right eye, necessitating surgical repair. The presence of HSV type 2 was confirmed in the vitreous. Visual acuity recovered completely after surgery and the patient was placed on a maintenance dose of oral acyclovir.

CONCLUSIONS

HSV type 2 is a rare cause of acute retinal necrosis in healthy patients. Bilateral involvement can occur in the fellow eye, even with a long delay. Acute retinal necrosis is a severe ocular inflammatory syndrome associated with a very poor visual outcome. It is caused by VZV, HSV type 1 and, less commonly, by HSV type 2. The disease can affect healthy patients and cause bilateral involvement in the fellow eye, even with a long delay.

Acute retinal necrosis in children caused by herpes simplex virus

PURPOSE

To report the diagnosis, management, and outcome of acute retinal necrosis syndrome in children.

METHOD

Case series of three consecutive children aged 11 years and younger who were diagnosed with acute retinal necrosis. In addition to full ocular and systemic examinations, the children underwent vitreous biopsy (Patients 1 and 2) or aqueous tap (Patient 3) for polymerase chain reaction analysis.

RESULTS

All patients had unilateral retinitis that was associated with preexisting chorioretinal scars, and two patients (Patients 1 and 3) had concurrent extraocular central nervous system abnormalities. Intraocular herpes simplex virus was detected in all three children: Type 1 in Patient 1 and Type 2 in Patients 2 and 3. In addition, all three children had a history of extraocular herpes simplex virus infection.

CONCLUSIONS

Retinitis associated with preexisting chorioretinal scars and detectable intraocular herpes simplex virus on polymerase chain reaction was common to all three children with acute retinal necrosis.

Herpes simplex encephalitis and bilateral acute retinal necrosis syndrome after craniotomy

PURPOSE

Acute retinal necrosis (ARN) syndrome is associated with members of the herpes virus family, but the mechanisms of infection remain unclear. The purpose of this study is to report a unique case of acute retinal necrosis syndrome associated with herpetic encephalitis in order to elucidate possible factors involved in herpetic central nervous system disease.

METHOD

Case report.

RESULTS

A 64-year-old woman who developed acute herpes simplex virus encephalitis associated with bilateral acute retinal necrosis syndrome after craniotomy for resection of a suprasellar craniopharyngioma is presented. The results of lumbar puncture, magnetic resonance imaging, and ophthalmologic examination are consistent with herpetic infection. The origin of acute retinal necrosis syndrome and the association of acute retinal necrosis syndrome with encephalitis are reviewed.

CONCLUSIONS

After craniotomy, we hypothesize reactivation of previously latent herpes simplex virus in the area of the inferior frontal lobe and optic chiasm. Reactivated virus may have migrated to the retina by axonal transport, through the optic nerves, to produce the acute retinal necrosis syndrome.

Pharmacomanipulation of HSV-1 induced chorioretinitis in mice

In the von Szily mouse model, intracameral inoculation of herpes simplex virus type-1 (HSV-1) results in inflammation of the ipsilateral anterior segment with relative chorioretinal sparing and destructive contralateral chorioretinitis. We studied the effect of the systemic antiviral agent acyclovir (ACV) and anti-HSV-1 antibody therapy in this model. Contralateral chorioretinitis developed in none of the 18 mice receiving ACV from post-inoculation day (pid) 1 (p < 0.0001), in 6 of 10 (60%) mice when treatment was delayed until pid 7 (p = 0.40) and in 14 of 18 (77%) controls. Contralateral disease developed in 8 of 16 (50%) mice that received anti-HSV-1 antibody from pid 1 (p = 0.02), in 13 of 16 (81%) treated from pid 5 (p = 0.64), in 7 of 8 (87.5%) treated from pid 7 (p = 1.0) and in 17 of 20 (85%) controls. We conclude that early treatment with ACV or anti-HSV-1 antibody reduces the incidence of contralateral chorioretinitis in mice.

MS strain of type 2 herpes simplex virus produces necrotizing retinitis in mice

Intracerebral inoculation of mice with the MS strain of type 2 herpes simplex virus (HSV-2) causes a brief encephalitis associated with multifocal central nervous system demyelination. Many of the mice develop unilateral or bilateral impairment of the pupillary light reflex. We have examined the development of ocular disease in inbred NIH mice inoculated intracerebrally with a low dose (10 pfu) of HSV-2 (MS). The resulting acute encephalitis was fatal in 30-50% of the mice. By 1 month after inoculation, the pupillary response to light was absent or impaired in approximately 80% of the surviving mice. Infectious virus could be isolated from the trigeminal ganglia and optic nerves from day 2 and from the eyes by day 4. Viral antigen was first immunohistochemically detectable in the optic nerves on day 5 and in the retinae on day 6. During the second week after inoculation up to half of the mice developed unilateral or bilateral necrotising retinitis associated with high titres of virus in the eyes and abundant viral antigen in the retinae. Electron microscopy confirmed the presence of viral particles in the retinae, in glia and degenerating neurons. No viral antigen was detected in the corneas and only rarely was antigen found in the ciliary body or iris. Infectious virus persisted longer in the eyes than in the trigeminal ganglia or optic nerves and could still be isolated from a few of the animals 2 weeks after inoculation. By 1 month the titres of virus within the eyes had fallen to undetectable levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Systemic viral infections and their retinal and choroidal manifestations

Viruses are one of the most common causes of infections involving the posterior segment of the eye. Such infections can occur either on a congenital or an acquired basis, and may affect primarily the retina or the choroid. Congenital cytomegalovirus (CMV) and rubella infections may result in retinitis. CMV retinitis is also the most common cause of acquired viral retinitis, primarily because of the acquired immunodeficiency syndrome (AIDS). Other types of viral retinitis, such as those caused by herpes simplex or herpes zoster, can occur in immunocompromised or immunocompetent individuals. Retinitis or choroiditis caused by viruses such as measles, influenza, Epstein-Barr virus, and Rift Valley fever virus, typically occurs subsequent to an acute viral systemic illness. The systemic and ocular manifestations, as well as the histopathology, laboratory tests, differential diagnoses, and treatment regimens for each of the individual viruses are discussed in detail.

Herpes zoster ophthalmicus

Herpes zoster ophthalmicus occurs worldwide, usually in healthy adults, but, increasingly in patients who are immunocompromised. After primary varicella infection (chickenpox), the virus lies dormant in the sensory ganglion until it becomes reactivated as zoster. Involvement of the ophthalmic branch of the trigeminal nerve is characterized early by corneal dysesthesia and dendritiform keratopathy, and these are self-limited. However, smoldering disease may cause pathological changes in the ocular structures through direct invasion of virus, secondary inflammation, and alterations of autoimmune mechanisms. Antiviral agents have demonstrated some success in resolving early signs and symptoms, but their role in preventing and treating late complications remains to be fully studied. Until a definitive antiviral agent is established, the benefits of steroid use in certain acute inflammatory processes outweight its risk of reducing host immunity. Corneal complications of herpes zoster ophthalmicus sometimes require surgical intervention.

Herpesvirus antibody levels in the etiologic diagnosis of the acute retinal necrosis syndrome

Quantitative antibody levels to three herpesviruses in acute and chronic sera from six patients with clinical signs of the acute retinal necrosis syndrome were consistent with a specific etiologic diagnosis only in the two cases associated with cutaneous herpes zoster. Available data on acute and convalescent antibody titers to herpes group viruses from these six patients in addition to data from 27 acute retinal necrosis cases from the literature disclosed that only 13 of the 33 patients (39%) had a diagnostic increase or decrease in herpes group viral antibody levels on serial sampling. Three patients had nondiagnostic changes in viral antibody levels despite positive vitreous cultures for herpesviruses. In contrast, a review of 25 cases from the literature with paired antiviral serum and intraocular fluid antibody levels suggested a more promising approach to the etiologic diagnosis of the acute retinal necrosis syndrome. By calculating the ratio of antiviral antibodies in intraocular fluid and serum, an etiologic diagnosis could be made in 12 of 14 (86%) of subacute and convalescent samples. The sensitivity of this method decreased to 72% (13 of 18) when fluids were obtained earlier in the course of the disease.

Decrease in the risk of bilateral acute retinal necrosis by acyclovir therapy

We reviewed the course of 54 patients who had unilateral acute retinal necrosis at initial examination. Thirty-one patients were treated with acyclovir, whereas 23 were not. Of the 31 patients treated with acyclovir, 27 (87.1%) had fellow eyes that remained disease-free throughout a median follow-up of 12 months. Of the 23 patients not treated with acyclovir, seven (30.4%) had fellow eyes that remained disease-free throughout a median follow-up of 11 months. Survival analysis indicated that the fellow eyes of the group of patients treated with acyclovir were more likely to remain disease-free than the fellow eyes of the group not treated with acyclovir (P = .0013). Two years after initial onset, the proportion of fellow eyes that remained disease-free was 75.3% for the group treated with acyclovir and 35.1% for the group not treated with acyclovir. These results suggest that acyclovir treatment reduces the risk of involvement of the fellow eye in patients with acute retinal necrosis.

Surgical management of retinal detachment associated with the acute retinal necrosis syndrome

We operated on nine eyes in eight patients with retinal detachment associated with acute retinal necrosis (ARN) syndrome. The patients were treated with scleral buckling, vitreoretinal surgery, or a combination of these treatments. Vitrectomised eyes underwent combinations of lensectomy, membrane dissection, scleral buckling, air-fluid exchange, endolaser photocoagulation, cryotherapy, and retinal tamponade with C3F8 gas or SF6 gas. Macular attachment was achieved in eight (89%) eyes. Vision improved in seven (78%) eyes, of which five (56%) achieved 20/200 or better vision. Three eyes that had received laser treatment posterior to areas of retinitis suffered retinal detachment despite this prophylactic treatment. Poor visual outcome resulted from viral infection of the optic nerve or macular involvement, macular hole formation, macular pucker, or hypotony.

Intrathecal antibody production against viruses of the herpesvirus family in acute retinal necrosis syndrome

Viruses of the herpesvirus family cause acute retinal necrosis syndrome, a devastating necrotic retinitis in immunocompetent individuals. Direct proof of the viral origin of this disease may be obtained by demonstration of the virus, viral antigens, or viral DNA in biopsy specimens of retinas. In search of alternative diagnostic methods, we analyzed cerebrospinal fluid and serum with enzyme-linked immunosorbent assays for virus-specific antibody activity. Intrathecally produced viral antibodies were found in three consecutive patients with acute retinal necrosis syndrome: herpes simplex type 2 in a 30-year-old woman with a history of suspected neonatal herpes encephalitis, herpes simplex type 1 in a 35-year-old man, and varicella-zoster virus activity in a 62-year-old woman. None of the patients had clinical signs indicating an acute disorder in the central nervous system. This serologic approach seems to be of value for the diagnosis of an associated intracerebral viral infection in cases of acute retinal necrosis syndrome.

Acute retinal necrosis syndrome

Acute retinal necrosis (ARN) is a rare syndrome with characteristic fundal appearances which can have devastating effects on vision. We present six cases (nine eyes) seen in the Medical Eye Unit of St Thomas's Hospital over the past six years and discuss the clinical features, aetiology, and management. Our findings support the present consensus that the condition is caused by varicella zoster virus (VZV) or herpes simplex virus (HSV). One of our patients, who was atypical in having common variable hypogammaglobulinaemia, had suffered a widespread zosteriform rash immediately prior to the onset of ARN, while another had suffered a herpes simplex uveomeningoencephalitis. All cases had characteristic confluent peripheral retinal necrosis, and three of the nine eyes developed retinal detachment. Retinal arteritis was a prominent and helpful diagnostic feature in one case. From combining all reports to date of this rare condition it is possible to conclude that ARN is unilateral in 65% of cases.

Diagnosis and management of the acute retinal necrosis (ARN) syndrome

The acute retinal necrosis (ARN) syndrome represents a specific pattern of clinical presentation for certain herpes virus infections in the posterior segment of the eye. The classically described triad of the ARN syndrome consists of (1) an arteritis and phlebitis of the retinal and choroidal vasculature, (2) a confluent, necrotizing retinitis that preferentially affects the peripheral retina, and (3) a moderate to severe vitritis. Anterior segment inflammation, optic neuritis, and late retinal detachment are also common features of this disorder. Definitive evidence now implicates at least two members of the herpes virus family; varicella zoster virus and herpes simplex virus as causative agents. This paper summarizes the clinical presentation, as well as the currently recommended treatment regimen for the ARN syndrome, highlighting recent advances that have resulted in a significant improvement in the visual prognosis for affected patients.

Rapidly progressive acute retinal necrosis secondary to herpes simplex virus, type 1

A systemically healthy 22-year-old man presented with unilateral acute retinal necrosis (ARN) that featured diffuse retinal whitening throughout the posterior retina, exudative retinal detachment, and a visual acuity of no light perception. Diagnostic vitrectomy revealed necrotic retinal cells containing intranuclear inclusions visible with light microscopy. On electron microscopy, viral particles consistent with a herpes family virus were detected. Culture of the vitrectomy specimen showed herpes simplex, type 1 (HSV 1) and rising convalescent serum ELISA titers to HSV 1 confirmed a recent infection. This case of ARN is unusual for its severity, early macular involvement, and development of exudative retinal detachment. In addition, it represents one of the few reported cases in which HSV 1 has been confirmed by both vitreous culture and serum titers as the etiologic agent. A review of the literature suggests that posterior segment inflammatory conditions secondary to HSV 1 can be associated with exudative retinal detachment, a clinical finding that may help differentiate such conditions from other infectious causes of chorioretinitis.

Rapidly progressive outer retinal necrosis in the acquired immunodeficiency syndrome

Two patients, both seropositive for the human immunodeficiency virus, developed rapidly progressive retinal necrosis associated with a systemic herpes zoster infection. The retinitis in these patients was characterized by primary involvement of the outer retina, with sparing of the inner retina and retinal vasculature until late in the disease process; a rapidly progressive course; poor response to intravenous acyclovir; and development of rhegmatogenous retinal detachment. In one of the patients, the retinitis was initially multifocal. Electron microscopy of a retinal biopsy specimen from one of the patients demonstrated virus particles consistent with a herpesvirus, and polymerase chain reaction disclosed herpesvirus in a retinal biopsy specimen of the other patient. This entity may represent a distinct form of acute retinal necrosis that is seen in immunocompromised individuals.

Isolation of a herpes simplex virus type 2 that is retinovirulent in mice

The virulence of a herpes simplex virus type 2 (HSV-2) isolated from the urine of a patient (SL) with acquired immunodeficiency syndrome (AIDS) and bilateral acute retinal necrosis (ARN), was investigated in mice. The ratio of plaque forming units (PFU) in fibroblasts to the 50% lethal dose (LD50) of HSV-2(SL) in mice was 10 fold more than the PFU to LD50 ratio of a neurovirulent HSV-2, strain 186. Further, HSV-2(SL) caused retinitis with and without lethal encephalitis in mice inoculated intracranially (i.c.). In contrast, mice inoculated with HSV-2(186) died of encephalitis without ocular disease. HSV-2(SL) was isolated from eye and/or brain tissue 1 to 15 days post i.c. inoculation. Ocular disease progressed from an initial mild chorioretinitis on day 8 to total retinal necrosis with panuveitis by day 11 in mice given 10 PFU of HSV-2(SL) i.c. HSV antigen was detected initially in the cells of the optic nerve and spread into the ganglial cells of the nerve fiber layer, the neurosensory cells of the inner nuclear layer, and the cells of the retinal pigment epithelium (RPE) between days 8 and 10. Thus, this study supports the concept that HSV neurovirulence varies between strains and presents a HSV-2 neurotransmission animal model of ARN.

Herpes simplex virus type 1. A cause of the acute retinal necrosis syndrome

The authors have isolated herpes simplex virus type 1 (HSV-1) from the vitreous of two patients with acute retinal necrosis. Clinical and laboratory data suggest that one case represented a primary HSV-1 infection, whereas the other case appeared to be a recurrent HSV-1 infection. In the primary case, changes on magnetic resonance imaging (MRI) suggest spread of the virus posteriorly to both optic tracts and the lateral geniculate ganglia. This case shares many features with the "von Szily" experimental model for HSV retinitis in the mouse.

Dual infection of retina with human immunodeficiency virus type 1 and cytomegalovirus

We examined retinal tissue from eight human immunodeficiency virus type 1 (HIV-1) seropositive patients with acquired immunodeficiency syndrome (AIDS) or AIDS-related complex for evidence of dual infection with HIV-1 and cytomegalovirus. Culture demonstrated simultaneous infection with HIV-1 and cytomegalovirus in two of 13 retinal specimens. This was confirmed by both immunofluorescence and immunohistochemical staining. Moreover, coinfection of individual cells with cytomegalovirus and HIV-1 was observed by immunohistochemical staining. Infection of retina with cytomegalovirus or HIV-1 alone occurred in one and six of the 13 retinal specimens, respectively. HIV-1 antigens were present on scattered cells in all layers of the retina and on retinal vascular endothelium. HIV-1 was isolated from retinal tissue derived from eyes both with and without gross ocular lesions. Cytomegalovirus antigens were found in all layers of the retina, but not on vascular endothelial cells. The atypically rapid clinical progression of retinitis in one of the patients with dual HIV-1 and cytomegalovirus infection suggests the possibility that interactions between these two viruses may influence retinal disease in patients with AIDS.

Ocular herpes simplex infection: pathogenesis and current therapy

Ocular herpes simplex disease has a variable pattern of manifestations and recurrences as a result of the site and extent of the infection, the host immunologic events, the trophic damage within ocular tissues, and the toxic effects of antiviral medications. Laboratory research has established a clinical model and a working hypothesis about the complex pathophysiologic features of the disease and the interaction of the virus with its host tissue. Recent studies have further defined the viral genome and its role in virulence and pathogenicity. Antiviral therapy is effective in some but not all aspects of the ocular infection. A proposed clinical classification of ocular herpes simplex is based on the manifestations associated with viral disease and those associated with the host response and the subsequent structural damage. A plan for medical and surgical management of ocular herpes simplex, based on current knowledge of the disease process, relates to the integrity of the epithelium and the presence of active viral disease.

Demonstration of varicella-zoster virus antigens in the vitreous aspirates of patients with acute retinal necrosis syndrome

Four cases of acute retinal necrosis (ARN) syndrome were studied virologically. Varicella-zoster virus (VZV) antigen was demonstrated by immunofluorescence in cells from vitreous aspirates of two cases. No herpes simplex virus (HSV) or cytomegalovirus (CMV) antigens were detected by the same technique. Antibody to VZV in vitreous fluid was present in two cases; however, it was not detected in sera. Although virus isolation was unsuccessful, these findings strongly suggest that VZV may play an important role in the etiology of ARN syndrome.

Acute retinal necrosis syndrome presenting with papillitis and arcuate neuroretinitis

Acute retinal necrosis (ARN) syndrome is a diffuse uveitis characterized by a peripheral necrotizing retinitis and retinal vasculitis. The authors document and discuss a case of ARN syndrome that initially presented with remarkable changes in the peripapillary retinal nerve fiber layer that they have termed arcuate neuroretinitis. These changes consisted of a well-defined arcuate band of retinitis paralleling the course of a parafoveal nerve fiber bundle. Evaluation of serial serum antibody titers suggests HSV-2 as a possible causative agent in this unique presentation of ARN syndrome.

Stress proteins accumulate in cultured retinal glial cells during herpes simplex viral infection

The production of stress- or heat-shock proteins (SP) which are defined by three monoclonal antibodies (TI56, TG5E and TG7A) were examined in cultured retinal glial cells with and without herpes simplex virus (HSV) infection. Indirect immunofluorescence showed that 80-90% of uninfected cells reacted with anti-glial fibrillary acidic protein (GFAP) and that 10-20% of uninfected cells were weakly labelled with anti-SP antibodies. By 6 hr after HSV infection, the proportion of GFAP labelled cells decreased to 60-70% whereas cells strongly expressing SP antigens were demonstrated. At 24 hr, GFAP+ cells were markedly reduced in number and immunolabelling with anti-SP antibodies was evident in approximately 50% of cells, directly demonstrating the accumulation of SP in cultured retinal cells after HSV infection. Double labelling with GFAP/TI56 indicated that 30% of GFAP+ cells were labelled with TI56 and 30-50% of TI56+ cells were also GFAP+, despite the abrupt loss of GFAP+ cells during HSV infection. These results indicate that SP normally expressed at low level are significantly upregulated in retinal glial cells following HSV infection.

Uveitis: a strategy for diagnosis

Uveitis may be the first presentation of a wide variety of underlying ocular and systemic diseases. It is important for the ophthalmologist to make a specific diagnosis in order to instigate specific therapy and give an accurate prognosis. The ability to recognise the clinical patterns of uveitis and to initiate appropriate investigations should form the basis of the ophthalmologist's management of the condition. To this end, we have considered uveitis under four major patterns of presentation--anterior uveitis, intermediate uveitis, posterior uveitis, and panuveitis--with subclasses within each of these four groups. We have outlined both the investigations which facilitate diagnosis of the possible underlying causes of inflammation and the interpretation of the results of such investigations.

Association of varicella zoster dermatitis with acute retinal necrosis syndrome

The authors report seven patients in whom the acute retinal necrosis (ARN) syndrome developed shortly after cutaneous varicella zoster infection. The length of time between the skin infection and ARN varied from 5 days to 3 months. Both eyes were affected in one of seven cases. The ophthalmic branch of cranial nerve V ipsilateral to an affected eye was involved by the zoster dermatitis in only two of the seven cases. The association lends further support to the proposal that herpes zoster virus is a major cause of ARN. A history of recent zoster dermatitis should be sought in patients with ARN.

Changing patterns of uveitis

We conducted a retrospective analysis of 600 patients with uveitis seen at the Estelle Doheny Eye Center to determine the frequency of occurrence of the various forms of uveitis and to see if the causes of uveitis have changed as compared with previous studies. In 402 cases (67.0%) we established a specific diagnosis based on history, physical findings, and laboratory studies: 167 cases (27.8%) involved primarily the anterior segment, 230 (38.4%) the posterior segment, and 111 (18.4%) occurred as panuveitis. Intermediate uveitis (pars planitis) was the single most frequently diagnosed uveitic entity and accounted for 92 cases (15.4%). We compared our findings with those of previously published studies and found that, as new diseases occur and improved diagnostic techniques become available, the differential diagnosis of uveitis continues to change.

Antiviral sensitivities of the acute retinal necrosis syndrome virus

Varicella zoster was isolated from the vitreous of a patient with the acute retinal necrosis (ARN) syndrome. We utilized a plaque reduction assay to determine the in vitro susceptibility of the ARN isolate to 6 antiviral drugs. The effective doses for 50% inhibition of plaque numbers were 5.3 microM for for acyclovir, 4.7 microM for DHPG, 8.7 microM for ARA-A, 100.7 microM for phosphonoacetic acid, 0.07 microM for BVdU and 2.4 microM for IUdR. Similar inhibitory values were obtained for the OKA vaccine strain of varicella zoster virus. These data do not support the notion that the ARN strain may represent a mutant of varicella zoster virus with significant alterations in either the viral thymidase kinase or DNA polymerase genes based upon its antiviral sensitivities. The implications of these results regarding the role of antiviral chemotherapy in the ARN syndrome are discussed.

Demonstration of herpes group virus in acute retinal necrosis syndrome

Tissue for pathologic examination was obtained from three cases of acute retinal necrosis syndrome. Virus particles belonging to the herpesvirus family were demonstrated in retinal biopsies from two patients, one of whom was immunosuppressed. Despite removal of large biopsy specimens, the retina has remained attached for 20 months postoperatively in one case and for three months in the other. In a third patient with acquired immune deficiency syndrome, the clinical course and postmortem immunopathology were suggestive of a herpes simplex virus infection, initially affecting the retina and subsequently the optic nerves, chiasm, tracts, and central nervous system. These cases illustrate that the virus associated with the acute retinal necrosis syndrome is easily demonstrable using vitrectomy and endoretinal biopsy in the acute phase of the disease, but may be difficult to demonstrate in chronically detached atrophic retinas.

Acute retinal necrosis syndrome following herpes zoster dermatitis

The acute retinal necrosis (ARN) syndrome has been recently linked to intraocular infection with one or more members of the herpesvirus family. The authors report two cases of ARN following herpes zoster skin eruptions, and one case following ipsilateral facial nerve palsy (Ramsay Hunt syndrome). Evaluation of serial serum antibody titers against cytomegalovirus (CMV), herpes simplex virus (HSV) (types 1 and 2), and varicella zoster (VZ) virus revealed diagnostic changes for VZ virus alone following the retinitis. Immune precipitation of radiolabeled VZ proteins by these sera followed by gel fractionation yielded radioimmune precipitation profiles characteristic of a recent zoster reactivation. These cases further implicate a central role for VZ virus infection in the etiology of the ARN syndrome.

Varicella zoster virus is a cause of the acute retinal necrosis syndrome

We studied two blind eyes enucleated during the active phase of the acute retinal necrosis syndrome. Both eyes showed similar histopathologic findings of necrotizing retinitis, retinal arteritis, and optic neuropathy. A virus morphologically consistent with a herpes group virus was found on electron microscopy and immunocytopathologic stains showed this virus to be varicella zoster in both cases. Varicella zoster virus was cultured from the vitreous of one of the eyes. We conclude that varicella zoster virus retinal infection is a cause of the acute retinal necrosis syndrome.

Intraocular acyclovir levels after subconjunctival and topical administration

Substantial levels of acyclovir were detected in the aqueous and vitreous of New Zealand rabbits at various time intervals following subconjunctival injection. Intravitreal penetration of acyclovir after topical application was poor.